A brake lining of the generic type is described in EP 0 784 761 B1. In the case of the brake lining which is described therein, a very uniform input of heat into the brake disk of a disk brake is achieved by way of a division of the overall lining area into a plurality of small lining elements and by way of a statically determined transmission of a brake application force of a caliper lever of a disk brake of a rail vehicle to the lining elements.
Here, the force of the caliper lever is distributed uniformly to respective halves of a lining carrier, on which the lining elements are secured, by a lining holder, on which the brake lining is secured.
Here, that force of the caliper lever which acts on a half of this type of the lining carrier is supported via in each case three carrier plates which are mounted on the lining carrier. Here, the force is distributed in such a way that all the carrier plates are loaded uniformly. Each of the carrier plates in turn divides the force which is exerted by the caliper lever, once again in a uniform manner, to the lining elements which are mounted on a carrier plate of this type.
An arrangement of this type of a carrier plate with lining elements which are held thereon via spherical bearings will be called a group element in the following text.
The group elements and also the three lining elements of a group element of this type lie on different orbital path diameters in relation to the brake disk, against which the lining elements bear in the case of a braking operation.
As a result of the positioning of the lining elements on different orbital path cross sections, the sliding velocity of the lining elements on the brake disk is also of different magnitude.
Owing to the different sliding velocities, in the case of an identical surface pressure of the lining elements, wear of the lining elements at a different speed and therefore an oblique position of the carrier plate and even of the entire lining holder can occur.
Here, the mounting of the lining elements on the carrier plate is designed in such a way that they lie on the brake disk with a surface pressure which is constant over the surface area.
Since, however, the local sliding velocity is not constant over the element surface area, each of the lining elements is also prone to oblique wear.
If the oblique wear is too great within a lining element or else within a group element, this can lead to single-sided contact of the lining elements on the carrier plate or the carrier plates on the lining carrier. As a result, the desired uniform distribution of force is impaired, as a result of which the contact pattern of the brake lining deteriorates.
Here, the performance of a disk brake is limited, inter alia, by the surface temperature which occurs on the friction face of the brake disk. In this way, hot cracks which grow at an excessive surface temperature occur, which hot cracks can reach impermissible sizes and can make a replacement of the brake disk necessary as a result.
The greater the fluctuations in the surface temperature on the brake disk, the lower the thermal energy which a brake disk can absorb without damage during a braking operation. Accordingly, a brake lining of optimum design introduces the thermal energy into the brake disk uniformly over the entire friction face, without producing relatively great temperature differences (for example, hotspots) on the surface.
In order to comply with the abovementioned requirements, the brake linings of rail vehicles, in particular of high speed trains, are of very complicated construction, with the result that they, as a wear part, cause a considerable proportion of the operating costs of rail vehicles of this type.
The wear of a brake lining is, inter alia, substantially dependent on the surface pressure between the brake lining and the brake disk and on the sliding velocity of the brake disk on the friction linings.ν′˜Pα·νβ,
where
v′ is the wear speed
P is the surface pressure
v is the sliding velocity, and
α, β are material parameters
[Saumweber, Gerum: “Grundlagen der Schienenfahrzeugbremse” [Foundations of the rail vehicle brake], Hestra-Verlag]
For the abovementioned reasons, oblique wear of the brake linings often occurs during operation of rail vehicles of this type. Therefore, the brake linings often have to be replaced, without it being possible to completely utilize the existing wear volume of the brake linings